Plan without dest. alternate!
Hello Hobbit
I would rather belive in a book, than what somebody tell at a GSR.
If you have the SWISS OM "A" you can read under Chapter 8.1 / page 28 para. 63.2 what you need, that one can plan without dest. alternat.
But still. I never would leave with this required fuel (legal amount), even if everything looks perfect!